The Best Ways Fruit Growers Can Test for Food Safety

In the current U.S. fruit industry, where just 1% of the population has the responsibility of producing the food that feeds us all, food safety is a vital component of all operations. But how do we verify that the fruits being produced are safe? Testing is a big part of that.

The three primary areas in which fruit growers must consider the need for appropriate testing are 1) product testing, 2) water-quality testing, and 3) environmental monitoring.

Product Testing is when the fruit itself is tested for contamination (such as from the growing environment or from contact surfaces). While product testing is not strictly required by food safety regulations, such as the Produce Safety Rule, it is something that each operation should take into consideration when evaluating its own unique risks. If there is a history of contamination associated with the fruit, such as recalls of cantaloupes and peaches, or if the fruit is considered high-risk, such as berries, then product testing may be warranted. Also, most fruits are often consumed raw, which heightens the potential need for product testing (if your fruit goes to these markets).

How it is done: The edible portion of the fruit can be sampled and sent off to a laboratory for testing to detect the presence of the relevant pathogens (such as Listeria or E. coli). Sampling techniques should be employed to ensure a representative sample of your crop is tested. Packhouses may take responsibility for product testing, as well. In these cases, it is best not to use “blended” or “grouped” samples, where product from multiple growers is mixed together, since this would not clearly indicate which grower or growers produced the contaminated fruit.

Water Quality Testing is required by the Food Safety Modernization Act (FSMA). Groundwater (wells) needs to be tested annually, and surface water (such as canals, ponds or creeks) likely needs to be tested multiple times throughout the growing season. Additionally, any water used during harvest (such as hydrocooling) or postharvest handling (such as washing) must be tested.

How it is done: The laboratory you use can provide water sample containers in which you will collect your samples. It is best to collect your samples at the farthest point in your system — that is, the point at which the water has traveled the farthest and is closest to contact with the fruit. It is important that water samples are delivered to the lab within hours of collection, so keep this in mind when selecting your lab and planning your collection activities.

Environmental Monitoring involves testing, not the fruit itself but the environment in which the fruit is handled. The highest priority for environmental monitoring should be given to surfaces that come into direct contact with the fruit, such as harvesting equipment or conveyer belts on a sorting line. This is referred to as Zone 1. Other areas that do not directly contact the fruit but are in close proximity (Zone 2) are also good indicators of whether contaminants are present in the environment.

How it is done: The lab you select will provide swabs for taking these samples, either for an upfront cost or with the charge assessed when samples are submitted for analysis. Follow their guidelines to rub swabs — sterile, wetted sponge material on a removable plastic handle — to sample the surfaces you intend to test. Each swab is used for only one location. Make sure your environmental monitoring program includes lists of the locations that need to be tested, as well as the frequency for each location, testing the Zone 1 locations at the highest frequency, then Zone 2, etc.

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LAB CREDENTIALS

In all the areas of testing mentioned above, it is important that you verify each laboratory’s accreditation. Ask for their certificate and ensure that it is valid (not expired) and covers the area of testing for which you are using their services. Labs can often provide sampling guidelines for you to use when collecting your samples for testing. When submitting samples, label each one as clearly and specifically as possible. It is vital that the test results be traceable back to your operation, crop, water source, facility location, and/or even the field/orchard and lot.

SOIL CONSIDERATIONS

An additional area of testing that may be needed is soil amendments. If your operation uses soil amendments, such as manure, that have not been through treatments like composting to reduce the presence of pathogens, you may need to test the manure to ensure you are not introducing contaminants to your production area. Perform a risk analysis that takes into consideration the timing of the application of the soil amendments (both within the growth cycle of the fruit and with respect to the harvest timing) as well as whether the soil amendment comes into contact with the edible portion of the fruit.

QUESTIONS TO PONDER

It is not enough to just include a testing program within your food safety plan. You must also provide management plans for what will be done in the case of adverse test results. For example, if a water test comes back with results above your established threshold, will you treat the water? Delay harvest? Seek a secondary processing market? If you receive a product test that indicates a pathogen, will you have to issue a recall? For an entire orchard? For your entire crop? These are the types of questions that need to be considered in the calm of pre-season planning when your program is being documented, and not as issues arise.

In some cases, multiple years of testing which resulted in no adverse results could justify discontinuing testing. Be sure to consult prevailing legislation as well as the requirements of any food safety certification program in which you participate. As with all things in food safety, detailed documentation is key. “If it isn’t documented, it didn’t happen!”